The Train-19 line was a direct response to the competitive/sales threat from the Industrial Rail line of trains. Same for MTH's introduction of the Rugged Rails line. In fact, MTH initially used Industrial Rail cars for their pre-production paint/photo samples.
With the passing of time, we've forgotten the industry and market buzz that UMD created with their Industrial Rail line of 3 rail trains. Very well reviewed by the train mags and well received by the buying public. Which took a big bite out of K-Line's sales.
So in a marketing move, K-Line basically rebranded a bunch of rolling stock for which the tooling already existed (save for the new trucks made for the Train-19 cars) with a $19.95 list price... hence the name Train-19. In my opinion, those truck sets on the Train-19 cars were the nicest K-Line ever made.
Industrial Rail was NOT a train manufacturer. The product line was created for UMD, United Model Distributors which was a wholesale/distribution outfit. Other train companies like Lionel, MTH and K-Line receive their products at their own warehouses, then sold their products to a wholesaler or distributor who in turn sold them to the hobby shops. Of course, with price increases at each step of the way. Dealers selling IR products could actually make some decent profit while still offering the consumer a discount, because they were purchasing them directly from the wholesaler. No middle man here.
As far as boxes, the Train-19 cars initially came in a redesigned blue, white and black box that said Train-19 on it. I don't think there was ever a clear plan for their box colors after this, other than for the scale products. The real 027 cars (the 5000-series that originated from the MARX tooling) came in mostly red boxes, but also mostly black and gold boxes too. The traditional type locos like the Budd cars, MP-15 and 027 Alco FA came in these black and gold boxes too for a long time.
But then when some of the enhanced features of the Alco-FA's were dropped (like both A units being powered) at least one Alco FA pair came in a red box that I recall: The white and red Seaboard Coast line, which had a powered A unit and then a dummy A unit, instead of both A units being powered. I'm certain there were others too.
@coach joe, there were no specific Train-19 locomotives. The loco your thinking of was the GP9 that was in the K-Line Husky line. The much more toy-like Husky line trains were from pre-existing tooling that K-Line made use of, just putting diecast 3-rail trucks on the rolling stock and using a single MP-15 motor truck (and a dummy truck) for the GP9.
@D500, I'm pretty sure the caboose you wrote of was in fact one of the Husky line trains, not Train-19. K-Line never had a woodside caboose in their traditional line of products, save for the scale side and the Husky line.